What is the process for applying for a Non-O Visa for dependent children in Thailand without marriage or custody papers?

The user successfully applied for a Non-O dependency visa for their Thai children in Mukdahan without marriage or custody documents, noting it was a simple process that did not require proof of funds. Required documents included passport photos, the children's birth certificate, and copies of relevant household registration and mother's identification. Comments clarified that this initial visa would only be a 90-day single entry, with an extension for a year requiring official documentation from the local amphur, and raised a question about the children's nationality if the mother is Thai.